1. Field of the Invention
The present invention relates to an apparatus and method for providing bypass on and off functionality for a motion sensor switch, such as a passive infrared detector adaptable for use with a lighting circuit. More particularly, the present invention relates to an apparatus and method for using the time delay adjustment device or another adjustment device of a motion sensor switch to set a desired output of the motion sensor switch, independent of detection or non-detection of motion by the motion sensor switch, to activate or deactivate a lighting circuit controlled by the motion detector switch, for example.
2. Description of the Related Art
A motion sensor switch, such as a Model 1WS-ZP-M motion sensor switch manufactured by Hubbell, Inc., includes a motion sensor, such as a passive infrared detector (PIR), and an ambient light level sensor, such as a photocell. Other motion sensor switches are described in U.S. Pat. No. 5,821,642 to Nishihira et al., U.S. Pat. No. 5,699,243 to Eckel et al., and U.S. Pat. No. 4,874,962 to Hermans, the entire contents of each being incorporated herein by reference. Motion sensor switches of this type can be used, for example, as an occupancy detector which shuts off lights in a room when the sensor detects that no one is present in the room, and turns on the lights in the room when a person enters the room. A motion sensor switch also can be used, for example, as a motion sensor for an alarm system.
During operation, the motion sensor of the motion sensor switch monitors an area, such as an office, conference room in a building, or a home, for the presence of movement. Specifically, the motion sensor detects a change in the infrared energy radiating from regions in the area monitored by different sensing lobes of the PIR detector, which generally have a pass band within the 8-14 xcexcm infrared range. If a person enters the monitored area, the person changes the amount of infrared energy being detected by the PIR detector. Therefore, the magnitude of the signal output by PIR detector, which is representative of the amount of detected infrared energy, will change. A motion sensor circuit in the motion sensor switch processes this signal, and provides a signal to a controller indicating that the amount of infrared energy received by the infrared detector has changed .
The controller interprets the signal provided by the motion sensor circuit, along with the signal provided by ambient light level sensor, to determine whether the lights in the monitored area should be activated. If the signal provided by ambient light level sensor indicates that the ambient light in the monitored area is low (e.g., very little natural light is present in the monitored area), the control circuit will turn on the lights in the monitored area. However, if the signal provided by ambient light level sensor indicates that the ambient light in the monitored area is sufficient (e.g., due to sunlight, etc.), the control circuit will not turn on the lights. In either event, control of the lights is based on the signals provided by the motion sensor and ambient light level sensor.
Motion sensor switches of this type also typically include a delay timing adjustment device, such as a potentiometer, which can be manually adjusted to set the delay time during which the lights will remain on after all occupants have left the monitored area. For example, if the delay timing adjustment device is adjusted to a 30-second setting, when all occupants leave and remain out of the monitored area for a period of time exceeding 30 seconds, the circuit of the motion sensor turns off the lights in the monitored area to conserve energy.
These motion sensor switches are disadvantageous because they are not capable of maintaining the lights in an active or inactive state regardless of the state of the motion sensor and ambient light level sensor. In other words, the motion sensor switches are incapable of bypassing their normal operation to maintain the lights in an xe2x80x9coffxe2x80x9d or xe2x80x9conxe2x80x9d state as desired. The ambient light level sensor is used to select a minimum level of light above which a lighting fixture is prevented from being switched and powered on following detected motion. A lighting control system operates in a daylight inhibit mode when the ambient light level is sufficient to render the switching of the lighting circuit unnecessary. Setting the ambient light level for daylight inhibit mode can be difficult if lighting circuits are switched on during the level setting process. The operation of the lighting fixtures during this process changes the detected amount of ambient light level to a higher foot-candle level than desired.
Therefore, in typical lighting circuit configurations, it is necessary to provide an xe2x80x9con/offxe2x80x9d switch in addition to the motion sensor switch to enable a user to bypass the operation of the motion sensor switch if desired. The on/off switch is separate and distinct from the motion sensor switch, and thus requires additional wiring to connect to the lighting circuit. Also, the setting of the on/off switch is generally different than that of the delay timing adjustment device of the motion sensor switch. Hence, to set the on/off switch, an operator usually needs to use a tool different from that which he or she would use to adjust the delay timing adjustment device. An operator can be further inconvenienced if the on/off switch is not positioned near the motion sensor switch.
Accordingly, a continuing need exists for a motion sensor switch having delay timing functions, as well as the capability of bypassing normal operation to maintain itself in an on or off condition, as desired, regardless of the detected conditions.
An object of the present invention is to provide a motion sensor switch, adapted for controlling activation and deactivation of a lighting circuit based on detected conditions, and having delay timing functions as well as bypass functions to maintain the lighting circuit in an on or off condition, as desired, regardless of detected conditions.
Another object of the invention is to provide a motion sensor switch, adapted for controlling activation and deactivation of a lighting circuit based on detected conditions, and having a delay timing adjustment device or other type of adjustment device which also functions as a bypass switch to control the motion sensor switch to maintain the lighting circuit in an on or off condition as desired.
A further object of the invention is to provide a delay timing and bypass switch, adapted for use with a motion sensor switch, to control the motion sensor switch to delay switching from a first output condition to a second output condition after the motion sensor switch senses a change in detected conditions, and also to control the motion sensor switch to maintain the first or second output condition, as desired, regardless of the detected conditions.
These and other objects of the invention are substantially achieved by providing an apparatus and method for controlling a motion sensor switch capable of detecting the presence of an object of interest within a monitored area by detecting a change in condition of the monitored area, and providing a first or second output condition in response to the detection result. The apparatus and method employs a setting adjustment device, such as a potentiometer, having a setting range which sets the duration of a delay period during which the motion sensor switch delays switching from the first output condition to the second output condition after sensing a change in condition of the monitored area, and a setting position at which the setting adjustment device outputs a first bypass signal. The apparatus and method further employs a bypass controller, such as a comparator circuit or software-implemented comparator, which, in response to the first bypass signal, controls the motion sensor switch to output the first or second output condition, irrespective of the detection result.
The setting adjustment device can further include another setting at which the setting adjustment device outputs a second bypass signal. The bypass controller can s therefore control the motion sensor switch to output the first output condition in response to the first bypass signal, and to output the second output condition in response to the second bypass signal.